Plastic processors who use profile extrusion methods continue to reduce the amount of plastic material used in every part made in order to reduce the cost of materials as well as increased the line speed of the extrusion equipment. Often, reducing the amount of material used results in weaker structural properties for the finished article.
Profile extruders, even those initially producing sheet extrusions, can create an article having an internal cavity in the article during the extrusion process. When the article has the internal cavity, plastic processors will often improve the structural properties of the finished article by adding a microcellular foam to the cavity using either a chemical or physical blowing agent to expand the foam.
Certain processes that create articles that, at least partially, fill the cavity extend the time periods for foaming and slow the line speed, which is not economically justified in view of the costly machine time. But, microcellular foaming does guarantee structural strength for profiles. Unless the profile wall uses a relatively thick, foam-filled, extruded plastic, the profile article will not be structural. In addition, in certain processes, the plastic material of the profile extruded article is different from the plastic material used for the foam core, rendering the article difficult to recycle. Recycling of articles after completion of their useful life is increasingly desirable for sustainability objectives as well as being included in certain regulations and specifications.